3D scanning

The paper presents the development of a Virtual Reality (VR) application to perform dives in the Christoforos Shipwreck. The huge wreck lies in the Panormos Bay of Skopelos island (Greece) at a depth of 45 meters. Based on a well-known methodology designed for ancient shipwrecks, the 3D reconstruction of the underwater site has been carried out by adjusting the workflow to survey modern shipwrecks. In particular, the methodology, based on photogrammetry, is capable to provide a highly detailed 3D reconstruction of the shipwreck in a few dives, considering issues like working depth, elevations, and thin elements modelling. Moreover, the paper describes the optimization of the 3D model and the software to be executed in low-performance Head Mounted Display (HMD) devices. The resulting VR application, realized for touristic purposes, recreates the exact ambient conditions inside and outside the water simulating the flora and fauna of the place, the coastline, allowing users to live a recreational and educational experience by virtual diving in the underwater site.

Keywords: computer graphics technologies , cultural heritage , modern shipwreck , underwater photogrammetry , virtual reality

Although Jerusalem is one of the most photographed places in the world, few works have focused on the existence of its former 800-year-old Maghrebi Quarter, located in the shadow of the Western Wall. Founded in 1193 by Saladin's son, al-Afdal ͑Ali to house Muslim pilgrims from North Africa (today Morocco, Algeria, Tunisia, and Libya), the Quarter was razed by Israeli bulldozers on the night of 10–11 June 1967. Its 1,000 or so inhabitants were forced to flee within hours. Silenced by the occupation of East Jerusalem as part of the Six-Day War, the existence of the Maghrebi Quarter faded behind the walls of history. This research paper describes how 55 years after its razing, the selection of a corpus of archives, combined with 3D technology and Interprofessional collaborations between historians and 3D designers enable making a forgotten history accessible again. Beyond a discussion on methods and technical process, this research paper aims to highlight the potential applications of the data set and the 3D model not only for scholarly research but also for pedagogical purposes, for instance.

Keywords: 3D reconstruction , archives , Jerusalem , Maghrebi Quarter , Open data

The documentation, conservation, and preservation of underwater archaeological sites is conventionally performed by divers in shallow waters. However, when dealing with significant depths, the sites can be inaccessible for humans, presenting significant challenges and risks, making these activities hazardous. Recently, the use of robotic platform such as remotely operated vehicles (ROVs) allows to overcome the difficulty of such a harsh environment. Nevertheless, professional-grade ROVs employed for this purpose are expensive and specifically designed with integrated advanced sensor systems for data acquisition and navigation. In the context of the MSCA-RISE H2020 Technological Consortium TO develop sustainability of underwater Cultural heritage (TECTONIC) project, a solution consisting of an optical payload and an acoustic localization system for low-cost ROV, was defined in order to support ROV pilots during documentation and monitoring activities. The project aims to preserve underwater cultural heritage (UCH) encompassing the selection of a commercially available ROV and the definition of a customized hardware/software (HW/SW) architecture. After market research, a suitable commercial off-the-shelf (COTS) low-cost ROV was defined and used as the foundation for integration. Mechanical, electric, and data interface modules were designed to seamlessly integrate and manage the sensor suite. The results of the integration demonstrate the potential of the chosen algorithms and the sensor suite for improved navigation and data collection in challenging underwater environments, where high-grade and expensive sensors are not available, thereby making more accessible the field of underwater survey missions.

Keywords: Underwater 3D Reconstruction , Underwater Cultural Heritage (UCH) , Underwater Localization , Underwater Mapping , Underwater Survey

Our cultural society has made remarkable advancements in creating digital models that depict the built environment, landscape, and reality. The advent of technologies such as terrestrial laser scanning and drone-based photogrammetry, coupled with sophisticated software capable of processing hundreds of photographs to generate point clouds, has elevated the significance of three-dimensional surveying in documentation and restoration. Point cloud processing and modeling software enable the creation of precise digital replicas of the investigated architecture, which can be scaled down and transformed into physically identical models. Through the export of STL files and the utilization of both subtractive and additive 3D printing technologies, tactile models resembling traditional manually crafted plastics can be obtained. An exemplary study focuses on the Gothic church of Santa Maria Alemanna in Messina, Italy, where laser scanner surveys and 3D prints using various technologies were applied to different parts of the building. The models were produced using a CNC milling machine and a 3D printer for fused deposition modeling. The sustainability of these production technologies was assessed through a Life Cycle Assessment, demonstrating the environmental advantages of additive manufacturing, including the use of materials with high recyclability and lower energy consumption. Additionally, the additive approach helps reduce processing waste.

Keywords: 3D printing , architecture recovery , cultural heritage , digital models , Life Cycle Assessment

This article introduces the Differential Entropy-based Compactness Index (DECI), a new metric for synthetically describing the spatial distribution of point clouds. DECI is founded on the differential entropy (DE) of point clouds, and if they depict a moving object distribution, the index enables real-time monitoring. Historical data analysis allows for the study of DECI trends and average values in defined intervals. Multiple practical applications are suggested, including risk assessment, congestion measurement, traffic control (including autonomous systems), infrastructure planning, crowd density, and health analysis. DECI's real-time and historical insights are valuable for decision-making and system optimization and hold potential as a feature in machine learning applications.

Keywords: 3D geometry distribution assessment , compactness index , differential entropy , point clouds , real-time , risk assessment

The present research is devoted to criminal investigation regarding the disappearance of two persons suspected to be kidnapped. The multi-disciplinary investigation based on the application of Forensic Geology and Botany allowed to ascertain the pre-mortem active presence of the victims on the event scene. The results of the geological and botanical characterization accomplished on the traces collected on the victims and their belongings (unknown samples) and soils and plants sampled on the scene of events (known samples), allowed to ascertain with a high degree of compatibility as the source of the unknown samples could derive from environments with characteristics similar to those found in the scene of events, suggesting a same common origin for the analysed unknown and known specimens. Peculiar minerals (calcium phosphate rich clays and dolostones), very abundant vegetal particles (thorns and seeds of Erica arborea), and algae associations were particularly useful in linking the victims to the scene of events. The results of the comparative analyses provided fundamental info-investigative data useful for establishing the pre-mortem active presence of the victims on the scene. Furthermore, the most significant positive matches found allowed reconstructing a very detailed walking carried out by the two victims on the event site in the hours immediately preceding their death. These implications were of paramount importance for the judicial system in the solution of this criminal case. The careful examination of mineral composition, textural features as well as of the peculiar assemblages of inorganic and vegetal materials from unknown and known specimens carried out in the case work revealed to be able to provide very strong geological and botanical evidence for supporting criminal investigations. These robust results were achieved by the experts involved in long time-consuming and careful activities and examinations. Furthermore, the geological and botanical investigation carried out demonstrated as the analyses of the relationships ascertained between the victims and the surrounding environment could also support the coroner's decision on the manner of death and facilitating the understanding of the event dynamics.

The use of non-destructive methods guaranteeing high standards of accuracy, speed, simplicity of use, and low costs may be crucial during judicial inspection aimed to reconstruct the spatial arrangement of crime scenes. Three-dimensional (3D) laser scanning and structured blue light scanning are two modern and advanced technologies widely used in many sectors of the sciences, included forensic sciences. Limiting itself to forensic applications, these technologies may be successfully used for acquiring point clouds in 3D space and reconstruct 3D virtual models of large-, medium-, and small-scale forensic scenarios. These two technologies were applied for reconstructing 3D virtual models from real crime scenes and geological evidence, respectively. Different investigative places and items were investigated and discussed. The research evidenced the advantages of using these modern techniques in order to assist investigators in: i) providing 3D virtual models for reconstructing even complex crime scenes occurred outdoor; ii) reconstructing of the dynamics of events, and iii) individuating possible interactions between the actors of the scene and the surrounding places.

igital representations of anatomical parts are crucial for various biomedical applications. This paper presents an automatic alignment procedure for creating accurate 3D models of upper limb anatomy using a low-cost handheld 3D scanner. The goal is to overcome the challenges associated with forearm 3D scanning, such as needing multiple views, stability requirements, and optical undercuts. While bulky and expensive multi-camera systems have been used in previous research, this study explores the feasibility of using multiple consumer RGB-D sensors for scanning human anatomies. The proposed scanner comprises three Intel® RealSenseTM D415 depth cameras assembled on a lightweight circular jig, enabling simultaneous acquisition from three viewpoints. To achieve automatic alignment, the paper introduces a procedure that extracts common key points between acquisitions deriving from different scanner poses. Relevant hand key points are detected using a neural network, which works on the RGB images captured by the depth cameras. A set of forearm key points is meanwhile identified by processing the acquired data through a specifically developed algorithm that seeks the forearm's skeleton line. The alignment process involves automatic, rough 3D alignment and fine registration using an iterative-closest-point (ICP) algorithm expressly developed for this application. The proposed method was tested on forearm scans and compared the results obtained by a manual coarse alignment followed by an ICP algorithm for fine registration using commercial software. Deviations below 5 mm, with a mean value of 1.5 mm, were found. The obtained results are critically discussed and compared with the available implementations of published methods. The results demonstrate significant improvements to the state of the art and the potential of the proposed approach to accelerate the acquisition process and automatically register point clouds from different scanner poses without the intervention of skilled operators. This study contributes to developing effective upper limb rehabilitation frameworks and personalized biomedical applications by addressing these critical challenges.

Keywords: 3D optical scanning , automatic point cloud alignment , depth cameras , neural network , upper limb anatomy

Additive manufacturing technology allows producing objects layer-by-layer starting from three-dimensional (3D) digital models. These 3D models can be drawn using CAD software or can be obtained starting from a real-world object, through reverse engineering (RE) techniques. RE process is today widely used in numerous industrial applications. It is a powerful tool for additive manufacturing, and their combination can greatly enhance product design as well as shorten the product development cycle. This chapter describes the main reverse engineering techniques – contact and noncontact active and passive systems – and the main phases that allow obtaining a 3D CAD model starting from a physical object.

Keywords: Active and passive methods , Contact and noncontact systems , Industrial CT scanning , Point cloud , STL format

This paper introduces an assistive system for diagnosing malignant pleural mesothelioma (MPM), a highly aggressive cancer caused by asbestos exposure. The system assists healthcare providers in accurately determining the tumor's volume and the appropriate dose of chemotherapy to administer. It employs a bi-level process that uses machine learning and deep learning techniques to classify CT images of lungs and then calculate the tumor's volume. The study addresses the challenges associated with deep nets, such as the need for large and diverse datasets, hyperparameter optimization, and potential data bias. Two CNN architectures, Inception-v3 and ResNet-50, were compared in terms of their features and performance, and three hyperparameters were optimized for each model to generate a broad range of training scenarios. To estimate the amount of cancer cells to target, CT images were used to calculate the tumor's volume. This process involved image pre-processing, cropping volume, registering and filtering images, filling holes, segmentation, and 3D reconstruction. The results demonstrate that the developed system utilizing CNN optimizations and reconstruction of 3D images from CT images can benefit the treatment of MPM patients. The system has the potential to improve the accuracy of MPM diagnosis and the effectiveness of chemotherapy, ultimately improving patient outcomes.

Keywords: 3D volume reconstruction , CNN , CT imaging , Malignant Pleural Mesothelioma

The standard method of design and manufacturing customised orthoses is still very time-consuming due to their often very complex shape. Different authors have tried to solve this problem but, unfortunately, the proposed approaches cannot be easily used in clinical practice because they require substantial interaction among medical staff and engineers or technicians. The aim of this work is to present the framework of a new design approach that could allow clinicians to easily model a customised orthosis, without a skilled technician develops the entire procedure. In particular, an automatic process based on Generative Design has been implemented. The obtained results have demonstrated that the implemented algorithm is simple to use and could allow also not-skilled users to design customised orthoses.

Keywords: CAD , Customised orthosis , Generative design , Reverse engineering

The sweep features of constant radius are particularly significant for the purposes of the historical-archaeological investigation and classification of ancient artifacts. The paper focuses on the automatic recognition of this specific class of features from triangulated 3D models experimentally acquired from cultural heritage objects. This is not a trivial problem. The ancient artifacts, although repeatable, are unique handmade pieces with a geometry commonly characterized by complex and non-analytical shapes. Their surfaces are also usually damaged and worn, so that the related geometric properties are altered or lost. The methodology proposed here is inspired by the one previously developed by the authors for the automatic segmentation of fillets, rounds and grooves from high-density triangulated models of mechanical components. The paper, in particular, focuses on the aspects of this methodology that must be tuned to allow the recognition of the sweep features of constant radius from archaeological finds. The methodology has been implemented and finally applied to an archaeological find acquired by a laser scanner.

Keywords: 3D archaeology , 3D digital models , Computer methods in archaeology , Feature recognition , Laser scanning

This study presents an alternative process for designing and manufacturing customized trays for dental-whitening treatments. The process is based on a digitized approach consisting of three main stages: design of a reference model, its manufacturing by AM, and thermoforming of the tray. The aim of the study was to develop a high-performance tray, able to guarantee comfort, safety, and efficacy for whitening treatments. To evaluate the patient's experience, some tests under real operating conditions were performed. Twenty people carried out a nighttime treatment of 14 days. Each patient was asked to assess the overall level of satisfaction and the comfort of the tray and its ability to retain the gel. Tooth whitening was also determined according to the VITAPAN scale. All patients involved in the study were satisfied and provided positive feedback about comfort and tightness of the tray. At the end of the treatment, 15 out of 20 patients achieved shade A1 on the VITAPAN scale. The mean improvement in color shades was about 7. These results confirmed the great potential of the proposed dental tray. Its use was proven to guarantee a high level of quality, flexibility, and customization of dental-whitening treatments, improving comfort, safety, and efficacy.

Keywords: additive technologies , bespoke dental trays , custom design , dental engineering , digital manufacturing , esthetic dentistry , tooth whitening

The 3D reconstruction of upper limb anatomy plays a significant role in many biomedical fields as ergonomics, motion rehabilitation, prosthesis design. Conventional manual measurements have been progressively replaced by 3D optical scanning in collecting and storing 3D anatomical data, thus increasing reliability and data accuracy, shortening, at the same time, the overall acquisition process. However, the real-time scanning of human body parts still represents a complex task since it is challenging to keep the arm in a stable position and avoid artifacts in the collected data. Also, optical undercut geometries often impair the 3D reconstruction's completeness. In this paper, a compact and low-cost 3D scanning system has been developed by integrating three D415 Intel RealSense cameras. The three depth cameras have been assembled in a circular rig to define a lightweight handheld scanner capable of carrying out 3D data acquisition in different scenarios. The optical system has been validated through anthropometric measurements on different subjects.

Keywords: 3D scanning , D415 Intel realSense , Depth-camera , Upper limb anatomy

Background: Orthopaedic and Trauma surgery is expected to undergo profound trans-formation as a result of the adoption of 3D technology. Among the various applications, patient specific manufacturing of splints and casts would appear to be, particularly in children, an interesting implementation. This study aims to assess the safety of patient specific 3D casts obtained with a newly developed 3D-scanning devise in a small case series. We therefore conducted a clinical outcome and pre-marketing study in 10 consecutive patients with distal radius fractures treated at an Academic Level I Pediatric Trauma Center. After the application of the 3D cast, patients underwent three consecutive evaluations in the following 21 days. The main outcome measurements were: pain, skin lesions and general comfort, and acceptance of the cast. The three domains were measured with the Visual Analogue Scale (VAS), the NPUAP/EPUAP classification and the Positive affect-Negative affect Scale for Children (PANAS-C), the Self-Assessment Manikin (SAM) clinical psychology tests and a Likert-type five item questionnaire, respectively. A final mechanical analysis of the cast was carried out to confirm product integrity. Results: The results obtained were consistently positive in the investigated domains of general comfort, efficacy of contention and mechanical integrity of the 3D-printed cast as well as in the practicability of the supply chain. Conclusions: This study provides Level IV evidence that patient specific 3D printed casts obtained with a specifically designed software were safe in the management of “buckle” fractures of the distal radius in children. These results encourage to extend the technology to the treatment of more demanding fractures.

Keywords: 3D printing , customized implants , orthopedic device , orthosis modeling , pediatrics , personalized medicine , reverse engineering

Home-based rehabilitation is becoming a gold standard for patient who have undergone knee arthroplasty or full knee replacement, as it helps healthcare costs to be minimized. Nevertheless, there is a chance of increasing adverse health effects in case of home care, primarily due to the patients' lack of motivation and the doctors' difficulty in carrying out rigorous supervision. The development of devices to assess the efficient recovery of the operated joint is highly valued both for the patient, who feels encouraged to perform the proper number of activities, and for the doctor, who can track him/her remotely. Accordingly, this paper introduces an interactive approach to angular range calculation of hip and knee joints based on the use of low-cost devices which can be operated at home. First, the patient's body posture is estimated using a 2D acquisition method. Subsequently, the 3D posture is evaluated by using the depth information coming from an RGB-D sensor. Preliminary results show that the proposed method effectively overcomes many limitations by fusing the results obtained by the state-of-the-art robust 2D pose estimation algorithms with the 3D data of depth cameras by allowing the patient to be correctly tracked during rehabilitation exercises.

Keywords: 3D model , Body tracking , Data fusion , Joints estimation , RGB-D camera

In the Cultural Heritage field, the choice of materials and exhibit structures is essential to properly house and support artifacts without causing damage or deterioration. This problem is even more evident in the case of finds made of stone for which, due to their weight, a proper selection and dimensioning of the relative supports is required. In fact, without adequate support, this can result in stress concentrations that could compromise the artifact's state of conservation. As a consequence, more often such exhibition supports are customized items, that are designed and manufactured to meet specific functional and artistic setup needs. In this context, the paper presents a design approach that combines topology optimization and additive manufacturing techniques to develop customized support structures which undertake the twofold purpose of preserving the artifact and making it available for the exhibition in the museum. The proposed approach has been assessed through the case study of a sandstone Ionic capital hosted in the Brettii & Enotri Museum in Cosenza (Italy). The proposed approach is therefore meant as a guideline for the design of customized exhibit supports especially in the case of sandstone artifacts with a complex shape or a conservation condition that requires specific attention.

Keywords: Additive manufacturing , Cultural heritage , Design methods , Exhibit supports , Photogrammetry , Topology optimization

Although computer vision techniques are widely and effectively used for terrestrial applications, the adoption of these techniques in underwater scenarios is often a challenging task. This is due to the water medium that degrades the quality of the acquired images requiring the use of specific methodologies for their correction and improvement. In this context, this paper presents a low-cost system for underwater 3D reconstruction and 3D measurements based on an off-the-shelf depth camera. The system consists of a Stereolabs ZED stereo camera and its waterproof housing designed to be fabricated through additive manufacturing technologies. A dedicated software has been developed to manage all the steps of the acquisition process, starting from the calibration phase and continuing for rectification, depth map computation, 3D scene reconstruction, and 3D measurement. A preliminary laboratory test has been carried out in a controlled environment to quantify system performance in accuracy of measurement.

Keywords: Calibration Techniques , Stereo Camera , Stereolabs ZED , Underwater 3D Reconstruction , Underwater Inspection

In hip arthroplasty, preoperative planning is fundamental to reaching a successful surgery. Nowadays, several software tools for computed tomography (CT) image processing are available. However, research studies comparing segmentation tools for hip surgery planning for patients affected by osteoarthritic diseases or osteoporotic fractures are still lacking. The present work compares three different software from the geometric, dimensional, and usability perspectives to identify the best three-dimensional (3D) modelling tool for the reconstruction of pathological femoral heads. Syngo.via Frontier (by Siemens Healthcare) is a medical image reading and post-processing software that allows low-skilled operators to produce prototypes. Materialise (by Mimics) is a commercial medical modelling software. 3D Slicer (by slicer.org) is an open-source development platform used in medical and biomedical fields. The 3D models reconstructed starting from the in vivo CT images of the pathological femoral head are compared with the geometries obtained from the laser scan of the in vitro bony specimens. The results show that Mimics and 3D Slicer are better for dimensional and geometric accuracy in the 3D reconstruction, while syngo.via Frontier is the easiest to use in the hospital setting.

Keywords: bio-imaging , CT image segmentation , hip surgery , orthopaedics , reverse engineering , software comparison , surgical planning

During the emergency caused by COVID 19 evidence has been provided about the risk of easily getting the virus by touching contaminated surfaces and then by touching eyes, mouth, or nose with infected hands. In view of the restarting of daily activities in presence, it is paramount to put in place any strategy that, in addition to social distancing, is capable to positively impact on the safety levels in public buildings by reducing such risk. The main aim of this paper is to conceive a design methodology, based on a digital, flawless, and sustainable procedure, for producing human-building interfacing solutions that allow anybody to interact in a safer and more comfortable way. Such solutions are focused on the adaptation of existing buildings features and are thought to be an alternative to sensor based touchless technology when this is not applicable due to economic or time constraints. The process is based on the integration of digital technologies such as 3D Scanning, Generative Design and Additive Manufacturing and is optimised to be intuitive and to be adaptive, hence, to be replicable on different kinds of surfaces. The design concept is finalised to generate automatically different products that meet geometry fitting requirements and therefore adapt to the specific geometries of existing handles. A specific case on Hands Free Door Handles is presented and the results of manufacturing and preliminary validation process are provided and discussed.

Keywords: Additive Manufacturing , Covid 19 , Generative Design , Reverse Engineering